Fuel systems for engines, e.g., diesel or petrol/gasoline engines, may include capless fuel filler necks on a fuel filler pipe coupled to a fuel tank for replenishing fuel in the tank. Such capless fuel filler necks may include sealing doors or flaps which remain closed to seal off the fuel system without a cap. A sealing door on a capless fuel filler neck may be opened by inserting a fuel nozzle into the fuel filler neck for refueling, for example. Capless refueling assemblies may be used in vehicles to reduce evaporative emissions as well as to simplify the refueling process.
Leak testing may be performed on fuel evaporative emissions systems to detect small leaks in order to reduce emissions. In some approaches, if a leak is detected following a refueling event for a vehicle with a capless refueling system, a message may be sent to the vehicle operator requesting that they manually clean out the capless refueling unit. For example, a refueling funnel may be packages onboard a vehicle with a capless refueling system, and in response to a leak detected after a refueling event, the vehicle operator may be instructed to manually clean the capless unit by inserting the funnel into the unit to clear dirt, salt, leaves, or other contaminants which may have entered the capless unit and thus caused the leak. If, after manually cleaning the capless unit, the leak is still present, then a diagnostic code may be set indicating degradation of the evaporative emission system.
However, the inventors herein have recognized that approaches which rely on manual cleaning of capless units when a leak is detected are intrusive and require a tool, e.g., a funnel, which may get misplaced. Further, such manual cleaning approaches may increase venting of fuel vapors into the atmosphere as the operator inserts the tool into the capless unit for cleaning.
In one example approach, in order to at least partially address these issues, a method for a vehicle with an engine and a capless refueling system comprises, in response to a leak detected following a refueling event, cleaning the capless refueling system using engine vacuum. For example, cleaning the capless refueling system using engine vacuum may be performed in response to no leak detected prior to the refueling event and a leak detected following the refueling event. Further, in some examples, if a leak is still detected after cleaning the capless refueling system using engine vacuum, a request may be sent to a vehicle operator to manually clean the capless refueling system.
In this way, engine vacuum may be used to clean debris introduced into a capless unit without relying on a manual, intrusive tool. Further, since engine vacuum is used in such an approach, fuel vapors may be kept inside the tank thus potentially reducing fuel emissions during the cleaning process.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.